Cellulose fibers are fibers from some plant or plant-based materials. Cotton, consisting mainly of cellulose fibers, is the most widely used natural fiber for producing soft and breathable textiles and clothing. Emerging research on cotton fabrics with versatile functionalities revolutionize the use of cotton fabrics as a wearable platform for tremendous applications. Moreover, recently demonstrated prototypes of textile supercapacitors and fiber supercapacitors boost textile-based energy storage applications. Such supercapacitors were constructed either by coating the textiles with functional thin film layers or by modifying the fibers with chemicals. However, direct conversion of cotton textiles into electrically active textiles for constructing supercapacitors remains a great challenge. Enabling textile energy storage requires that the textiles have good electrical conductivity. A well established method is polymer coating, in which individual fibers are uniformly coated with a smooth and coherent layer of conductive polymers. The drawback of this method is that the obtained conductive fabrics show aged decay of electrochemical stability. Recently, a solution-based technique has been developed to convert cotton textiles into conductive textiles by conformally coating the cellulose fibers with carbon nanotubes (CNTs) or graphene thin films. The three-dimensional (3D) high-surface-area characteristic of such textiles facilitates the access of electrolytes, enabling high electrochemical performance of textile supercapacitors. However, the employment of organic surfactant for preparing CNT “ink” is not enviromentally benign. The other drawback is that the use of CNTs increases the cost of the device, which more or less deters their technological applications.
Therefore, a need exists for improved methods and materials for textile energy storage.